WO2023105733A1

WO2023105733A1 - Method for grinding gear and gear grinding device

Info

Publication number: WO2023105733A1
Application number: PCT/JP2021/045442
Authority: WO
Inventors: 克仁吉永; 滉明吉田
Original assignee: 株式会社ジェイテクト
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2023-06-15

Abstract

This method for grinding a gear comprises a grinding step (Sb) for grinding a tooth flank of a gear (Gb1) by: making an axial intersection angle between a rotational axis (B2) of a workpiece (W2) and a rotational axis (C) of a thread-shaped grinding wheel (T) a combined axial intersection angle (θ2) obtained by combining a reference axial intersection angle (θ1) with a corrected axial intersection angle (Δθ); rotating the thread-shaped grinding wheel (T) and the workpiece (W2) in a synchronized manner; and relatively moving the thread-shaped grinding wheel (T) in a direction parallel to the rotational axis (B2) of the workpiece (W2). The reference axial intersection angle (θ1) is an axial intersection angle determined on the basis of a torsion angle (ϕw) on a reference circle of the gear (Gb1) and a torsion angle (ϕt) on a reference circle of the thread-shaped grinding wheel (T). The corrected axial intersection angle (Δθ) is an axial intersection angle for forming a grinding mark (Gr_W2), which is formed on the tooth flank of the gear (Gb1) by the thread-shaped grinding wheel (T), in a direction inclined at a predetermined angle (Σ) with respect to a tooth trace direction (D_Tr).

Description

GEAR GRINDING METHOD AND GEAR GRINDING APPARATUS

The present disclosure relates to a gear grinding method and gear grinding apparatus.

Patent Document 1 describes that noise is generated due to the influence of minute steps formed on the tooth flanks of the gears when the gears are meshed. A minute step on the tooth flank of the gear is produced, for example, by grinding the tooth flank of the gear with a grindstone. Specifically, when the tooth surface of the gear is ground by the abrasive grains of the grindstone, fine groove-like grinding streaks are formed on the tooth surface of the gear in the direction in which the abrasive grains advance at the grinding point on the tooth surface. be done. In general, fine groove-like grinding streaks are formed in a direction parallel to the tooth trace direction of the tooth surface of the gear. That is, due to the plurality of grinding streaks, steps are formed in the tooth depth direction on the tooth flank of the gear. Patent Document 1 describes that after grinding the tooth flank of the gear with a grindstone, honing or processing with a dressing gear is performed in order to reduce the step on the tooth flank.

JP-A-2000-52145

However, with conventional methods, after grinding with a grindstone, additional processing such as honing or processing with a dressing gear is required in order to reduce the step on the tooth surface of the gear. Additional processing causes an increase in processing man-hours and an increase in processing costs.

The present disclosure has been made in view of such problems, and provides a gear grinding method and a gear grinding apparatus that can reduce noise due to the influence of steps on the tooth flanks of the gears in meshing the gears without performing additional processing. is trying to provide.

One aspect of the present disclosure is a gear grinding method for grinding a tooth surface of a gear using a threaded grindstone,
The crossed axes angle between the rotation axis of the workpiece and the rotation axis of the threaded grindstone is set to a composite crossed axes angle obtained by synthesizing the reference crossed axes angle and the corrected crossed axes angle, and the threaded grindstone and the workpiece are rotated synchronously. , a grinding step of grinding the tooth surface of the gear by relatively moving the threaded grindstone in a direction parallel to the rotation axis of the workpiece;
The reference crossed axis angle is a crossed axis angle determined based on the torsion angle on the reference circle of the gear and the torsion angle on the reference circle of the threaded grindstone,
The correction crossed axis angle is a crossed axis angle for forming grinding streaks formed on the tooth surface of the gear by the threaded grindstone in a direction inclined at a predetermined angle with respect to the tooth trace direction. It is in the gear grinding method.

Another aspect of the present disclosure is a gear grinding device that grinds the tooth surface of a gear using a threaded grindstone,
The crossed axes angle between the rotation axis of the workpiece and the rotation axis of the threaded grindstone is set to a composite crossed axes angle obtained by synthesizing the reference crossed axes angle and the corrected crossed axes angle, and the threaded grindstone and the workpiece are rotated synchronously. , a grinding processing unit that grinds the tooth surface of the gear by relatively moving the threaded grindstone in a direction parallel to the rotation axis of the workpiece,
The reference crossed axis angle is a crossed axis angle determined based on the torsion angle on the reference circle of the gear and the torsion angle on the reference circle of the threaded grindstone,
The correction crossed axis angle is a crossed axis angle for forming grinding streaks formed on the tooth surface of the gear by the threaded grindstone in a direction inclined at a predetermined angle with respect to the tooth trace direction. It is in the gear grinding machine.

When grinding the tooth flank of a gear using a threaded grindstone, the crossed axis angle between the rotation axis of the workpiece and the rotation axis of the threaded grindstone is set. The crossed axes angle obtained by the torsion angle on the reference circle of the gear and the torsion angle on the reference circle of the threaded grindstone is defined as the reference crossed axes angle. For example, when the torsion angle on the reference circle of the gear is 0°, the reference crossed axis angle matches the torsion angle on the reference circle of the threaded grindstone. If the torsion angle of the gear on the reference circle is not 0°, the reference crossed axis angle is an angle that takes into consideration the torsion angle of the gear on the reference circle with respect to the torsion angle on the reference circle of the threaded grindstone.

If the crossed axes angle is set to the reference crossed axes angle and the gear tooth flank is ground, the grinding streaks formed on the gear tooth flank by the threaded grindstone are parallel to the tooth trace direction of the tooth flank. direction. Therefore, according to the above-described gear grinding method and gear grinding apparatus, the crossed axes angle between the rotation axis of the workpiece and the rotation axis of the threaded grindstone is a synthetic crossed axes obtained by synthesizing the reference crossed axes angle and the corrected crossed axes angle. It is angled.

The corrected crossed axis angle is the crossed axis angle for forming the grinding streaks formed on the tooth surface of the gear by the threaded grindstone in a direction inclined at a predetermined angle with respect to the tooth trace direction. That is, by setting the crossed axes angle during grinding to a combined crossed axes angle obtained by combining the reference crossed axes angle and the corrected crossed axes angle, the grinding streaks are not parallel to the tooth trace direction, but are direction.

Since the grinding streaks can be formed in a direction inclined to the tooth trace direction, for example, when the gear to be ground and the mating gear are meshed, the grinding streaks are formed in the direction of engagement on the tooth surface of the gear to be ground. The extending directions can be matched. If the two directions are the same, the mating gear will not move over the grinding streaks on the tooth flanks during the progress of the meshing of the gears. Since the grinding striations are not driven over, the noise generated in the meshing of the gears can be reduced.

Further, even if the direction in which the grinding streaks extend does not coincide with the direction in which the meshing advances, it is possible to reduce the movement of riding over the grinding streaks by bringing the extending direction of the grinding streaks closer to the direction in which the meshing advances. . As a result, it is possible to reduce the noise generated in the meshing of the gears.

As described above, according to the above aspect, it is possible to provide a gear grinding method and a gear grinding apparatus capable of reducing noise due to the influence of steps on the tooth flanks of the gears in meshing the gears without performing additional processing. .

It should be noted that the symbols in parentheses described in the claims indicate the correspondence with specific means described in the embodiments described later, and do not limit the technical scope of the present invention.

It is a figure which shows a gear grinding apparatus. It is the figure which looked at the gear grinding apparatus of FIG. 1 from the left. (a) is a diagram showing a meshing state of a drive gear and a driven gear, and (b) is a diagram for explaining a meshing line and a meshing advancing direction in the case of a helical gear. FIG. 4 is a diagram for explaining the mechanism of meshing noise generation, in which (a) shows a case in which the grinding streaks are aligned with the direction in which the meshing progresses, and (b) shows a case in which the grinding streaks are inclined in the direction in which the meshing progresses. It is a figure which shows. 4 is a flow chart showing processing by a grinding condition determination unit that constitutes the gear grinding apparatus according to Embodiment 1. FIG. FIG. 6 is a diagram for explaining the reference crossed axis angle determination step S3 in FIG. 5 , (a) shows the state of the threaded grindstone and the workpiece, and (b) is grinding of the gear of the threaded grindstone and the workpiece. (c) shows a view of the threaded grindstone and the workpiece viewed from the rotation axis of the threaded grindstone. FIG. 6 is a diagram for explaining the reference crossed axis angle determination step S3 in FIG. (b) is a view showing part of the grinding streaks on the tooth surface of the workpiece, and (c) is a perspective view showing the grinding streaks on the tooth surface of the gear of the workpiece. FIG. 6 is a diagram for explaining the corrected crossed axis angle determination step S4 in FIG. 5 , (a) shows the state of the threaded grindstone and the workpiece, and (b) is grinding of the gears of the threaded grindstone and the workpiece. (c) shows a view of the threaded grindstone and the workpiece viewed from the rotation axis of the threaded grindstone. FIG. 6 is a diagram for explaining the correction crossed axis angle determination step S4 of FIG. (b) is a view showing part of the grinding streaks on the tooth surface of the workpiece, and (c) is a perspective view showing the grinding streaks on the tooth surface of the gear of the workpiece. FIG. 4 is a diagram showing a grinding point on the tooth surface, a velocity vector, and a tooth surface normal component vector on the tooth surface of the gear of the workpiece; FIG. 4 is a diagram showing a grindstone velocity vector, a grindstone normal component vector, and a tangential vector in a convex blade of a threaded grindstone. FIG. 2 is a diagram showing grinding points on the tooth surface of the gear of the workpiece and grinding wheel shape points of the threaded grinding wheel in Embodiment 1; FIG. 4 is a diagram showing a grinding point of a tooth surface of a gear of a workpiece and a grindstone shape point of a threaded grindstone in a reference example. FIG. 10 is a perspective view showing the direction of engagement and grinding streaks in the case of a spur gear in Embodiment 2; FIG. 10 is a diagram showing a threaded grindstone in Embodiment 3;

(Embodiment 1)
1. Gear grinding device 1
The configuration of the gear grinding machine 1 will be described with reference to FIGS. 1 and 2. FIG. The gear grinding device 1 uses a threaded grindstone T to grind the tooth flanks of gears. Specifically, the gear grinding apparatus 1 grinds the tooth flanks of a gear-shaped workpiece W using a threaded grindstone T to form desired gear tooth flanks.

Specifically, as shown in FIG. 2, the gear grinding machine 1 sets the crossed axes angle between the rotation axis B of the workpiece W and the rotation axis C of the threaded grindstone T to the combined crossed axes angle θ2. The combined crossed axes angle θ2 is an angle obtained by combining the reference crossed axes angle θ1 and the corrected crossed axes angle Δθ. The reference crossed axis angle θ1 and the corrected crossed axis angle Δθ will be described later.

Then, the gear grinding machine 1 rotates the threaded grindstone T around the C axis, which is the central axis of the threaded grindstone T, and rotates the workpiece W around the B axis, which is the central axis of the workpiece W. The gear-shaped tooth flanks of the workpiece W are ground by relatively moving the threaded grindstone T in the central axis direction of the workpiece W. As shown in FIG.

Therefore, the gear grinding machine 1 is configured so that the workpiece W and the threaded grindstone T can be moved relative to each other in the directions of the three orthogonal axes. Further, in the gear grinding machine 1, the workpiece W is rotatably provided around the B axis, the threaded grindstone T is provided rotatably about the C axis, and the relative posture between the workpiece W and the threaded grindstone T is changed. For this purpose, the workpiece W or the threaded grindstone T is rotatably provided.

For the gear grinding device 1, for example, a 6-axis processing machine, that is, a processing machine having 3 straight axes and 3 rotating axes is applied. In this embodiment, the gear grinding machine 1 enables the workpiece W to rotate about the B axis, the threaded grindstone T to rotate about the A axis and the C axis, and the threaded grindstone T to rotate in the X axis direction and the Y axis direction. It is movable in the axial direction and the Z-axis direction. The A-axis is an axis perpendicular to the rotation axis B of the workpiece W and the rotation axis C of the threaded grindstone T. The B-axis coincides with the center axis of the workpiece W. The C-axis coincides with the central axis of the threaded grindstone T. The mechanical configuration of the gear grinding machine 1 is not limited to the above, and various configurations can be applied. For example, the gear grinding machine 1 can apply a horizontal machining center having another configuration, a vertical machining center, or the like.

The gear grinding machine 1 includes, for example, a bed 2, a column 3, a Y-axis slide 4, a rotating member 5, a grindstone support member 6, a threaded grindstone T, a workpiece support member 7, a grinding condition determination unit 8, and a grinding processing unit 9. Prepare. The bed 2 is installed on the installation surface. The column 3 is guided by an X-axis guide provided on the upper surface of the bed 2 so as to be movable in the X-axis direction (horizontal direction in FIG. 1) with respect to the bed 2 . Although not shown, the column 3 is driven by a ball screw mechanism, a linear motor, or the like.

The Y-axis slide 4 is provided movably in the Y-axis direction (vertical direction in FIG. 1) with respect to the column 3 by being guided by a Y-axis guide provided on the side surface of the column 3 extending in the vertical direction. The rotary member 5 is provided on the Y-axis slide 4 and is provided rotatably around the A-axis, which is the horizontal axis. The rotating member 5 is provided rotatably within a range of 360°, for example.

The grindstone support member 6 is guided by a Z-axis guide provided on the rotating member 5 and provided so as to be movable in the Z-axis direction. The Z-axis direction changes as the rotary member 5 rotates around the A-axis. The Z-axis direction in the initial state is, for example, a horizontal direction perpendicular to the X-axis direction and the Y-axis direction.

The grindstone support member 6 supports the threaded grindstone T so as to be rotatable around the C axis. The C-axis is aligned with the central axis of the threaded grindstone T and parallel to the Z-axis direction. The threaded grindstone T has a helical convex blade protruding radially outward. The threaded grindstone T may have a single thread or may have multiple threads. The threaded grindstone T has a plurality of helical convex blades in the case of a multi-threaded thread. The workpiece support member 7 is provided on the bed 2 and supports the workpiece W rotatably around the B axis.

The grinding condition determination unit 8 is configured with at least a processor (arithmetic processing unit). The grinding condition determination unit 8 determines grinding conditions including the convex shape of the threaded grindstone T and the combined crossed axis angle θ2 (grinding condition determination step Sa). The combined crossed axes angle θ2 is an angle obtained by combining the reference crossed axes angle θ1 and the corrected crossed axes angle Δθ. A method for determining the grinding conditions will be described later.

The grinding processing unit 9 includes at least a processor (arithmetic processing unit). The grinding processing unit 9 uses the threaded grindstone T to grind the tooth surface of the gear of the workpiece W based on the determined grinding conditions (grinding step Sb). A method of grinding the tooth surface of the gear on the workpiece W by the grinding processing section 9 of the gear grinding apparatus 1 is performed as follows. In this embodiment, the rotating member 5 is rotated about the A axis by a predetermined angle in order to obtain a grinding posture in which the crossed axis angle between the rotation axis B of the workpiece W and the rotation axis C of the threaded grindstone T is θ2. Subsequently, the grinding processing section 9 rotates the workpiece W and the threaded grindstone T synchronously. Specifically, the workpiece W is rotated around the B-axis and the threaded grindstone T is rotated around the C-axis, and both rotations are synchronized.

Subsequently, the column 3 is moved in the X-axis direction, the Y-axis slide 4 is moved in the Y-axis direction, and the grindstone support member 6 is moved in the Z-axis direction, thereby moving the threaded grindstone T to the initial grinding position. Moving. Subsequently, by moving the Y-axis slide 4, the threaded grindstone T is moved in the direction of the center axis of the workpiece W (in the direction parallel to the rotation axis B), and the gear tooth surface of the workpiece W is ground. .

In the present embodiment, the gear grinding method by the gear grinding apparatus 1 performs processing (grinding condition determination step Sa) by the grinding condition determination unit 8, and then performs processing (grinding step Sb) by the grinding processing unit 9. It's about.

2. Gear engagement advancing direction D_La
The mesh advancing direction D_La will be described with reference to FIG. As shown in FIG. 3(a), the drive gear Ga and the driven gear Gb are brought into mesh. Also, the driving gear Ga and the driven gear Gb are gears having a helix angle.

In this case, as shown by the dashed line in FIG. 3B, on the tooth surface of the driven gear Gb, the contact line (engagement line) La with the driving gear Ga is is sloping. Specifically, first, the tooth flank corner Ea, which is one end in the tooth addendum and tooth trace direction D_Tr, of the tooth surface of the driven gear Gb is engaged, and the tooth flank, which is the other end in the tooth root and tooth trace direction D_Tr, is engaged. A contact line (engagement line) La moves toward the corner Eb.

3. Mechanism of Generation of Mesh Noise and Method of Suppressing Mechanism of generation of mesh noise and method of suppressing it will now be described with reference to FIG. The noise generated when the driving gear Ga and the driven gear Gb are meshed is affected by the steps formed on the tooth flanks of the driving gear Ga and the driven gear Gb. Here, the tooth surface of the driven gear Gb will be described.

FIG. 4(a) shows a case where the grinding streak Gr1 formed on the tooth surface of the driven gear Gb1 extends in an oblique direction with respect to the tooth trace direction D_Tr and the tooth depth direction D_Hi. FIG. 4B shows a case where the grinding streak Gr2 formed on the tooth surface of the driven gear Gb2 extends in a direction parallel to the tooth trace direction D_Tr.

The grinding streaks Gr1 and Gr2 are fine grooves formed by grinding the tooth flanks of the driven gears Gb1 and Gb2 with the threaded grindstone T shown in FIG. The extending direction of the grinding streaks Gr1 and Gr2 coincides with the direction in which the contact abrasive grains, among the abrasive grains constituting the threaded grindstone T, which contact the tooth flanks of the driven gears Gb1 and Gb2 travel.

On the tooth flank of the driven gear Gb1 shown in FIG. 4(a), the contact abrasive grains of the threaded grindstone T advance in a direction oblique to the tooth trace direction D_Tr and the tooth depth direction D_Hi. In particular, in the driven gear Gb1, the extending direction of the grinding streaks Gr1 coincides with the mesh advancing direction D_La. The grinding streaks Gr1 are formed in a direction inclined at a predetermined angle Σ with respect to the tooth trace direction D_Tr. However, in detail, the grinding streak Gr1 is not linear, but is composed of arcs with a large number of small angles, so the predetermined angle Σ has an angle range.

On the other hand, on the tooth surface of the driven gear Gb2 shown in FIG. 4(b), the contact abrasive grains of the threaded grindstone T advance in a direction parallel to the tooth trace direction D_Tr. Therefore, in the driven gear Gb2, the extending direction of the grinding streaks Gr2 does not match the mesh advancing direction D_La.

In the driven gear Gb1 shown in FIG. 4(a), in the process of meshing with the driving gear Ga, the meshing point does not get over the grinding streak Gr1. Therefore, noise caused by the engagement point overcoming the grinding streak Gr1 does not occur. On the other hand, in the process in which the driven gear Gb2 shown in FIG. 4B is engaged with the drive gear Ga, the point of engagement overcomes the grinding streak Gr2. Therefore, noise is generated due to the meshing point crossing over the grinding streak Gr2.

In this manner, as shown in FIG. 4A, the extending direction of the grinding streaks Gr1 is set to coincide with the mesh advancing direction D_La. ) can be suppressed. Even if the extending direction of the grinding streaks Gr1 does not completely match the direction of progress of meshing D_La, the occurrence of meshing noise is suppressed as the direction of extending of the grinding streaks Gr1 approaches the direction of progress of meshing D_La. can be done. Therefore, even if the direction in which the grinding streaks Gr1 extend does not completely match the meshing direction D_La, meshing noise can be reduced by bringing the extending direction of the grinding streaks Gr1 closer to the meshing direction D_La. Works effectively.

4. Processing by Grinding Condition Determining Unit 8 Processing by the grinding condition determining unit 8 (grinding condition determining step Sa) will be described with reference to FIGS. 5 to 12. FIG. As described above, the grinding condition determination section 8 determines the grinding conditions including the convex edge shape of the threaded grindstone T and the crossed axis angle θ2. In particular, as shown in FIG. 4(a), the grinding condition determination unit 8 determines the grinding conditions such that the extending direction of the grinding streak Gr1 can be matched with the target direction.

The grinding condition determination unit 8 performs a gear specification acquisition step S1, a threaded grindstone specification step S2, a reference crossed axes angle determination step S3, a corrected crossed axes angle determination step S4, a combined crossed axes angle determination step S5, and a convex edge shape. A determination step S6 is executed.

The grinding condition determining unit 8 first acquires the specifications of the gear Gb to be ground (S1). The specifications of the gear Gb include the module, normal pressure angle, helix angle φw on the reference circle, number of teeth, shift coefficient, reference pitch circle diameter, base circle diameter, tip circle diameter, and root circle diameter.

Next, the grinding condition determination unit 8 determines the specifications of the threaded grindstone T (S2). The specification of the threaded grindstone T is determined as follows. The grinding condition determination unit 8 determines the pressure angle of the threaded grindstone T based on the acquired specifications of the gear Gb (S21). Subsequently, the grinding condition determination unit 8 determines the grindstone module and pitch (S22). Subsequently, the grinding condition determination unit 8 calculates the torsion angle φt on the reference circle corresponding to the grindstone diameter (S23).

Subsequently, the reference axis crossing angle θ1 is determined (S3). The reference axis crossing angle θ1 will be described with reference to FIGS. 6 and 7. FIG. In determining the reference crossed axis angle θ1, the description will be made by assuming that the workpiece is W1 and the rotation axis of the workpiece W is B1. The workpiece W1 and the rotation axis B1 are used separately from the workpiece W2 and the rotation axis B2 in determining the corrected crossed axis angle Δθ, which will be described later.

FIGS. 6(a) and 6(b) are views seen from a direction orthogonal to the rotation axis B1 of the workpiece W1 and orthogonal to the rotation axis C of the threaded grindstone T. FIG. As shown in FIGS. 6A and 6B, the reference crossed axes angle θ1 is the crossed axes angle between the rotation axis B1 of the workpiece W1 and the rotation axis C of the threaded grindstone T. As shown in FIGS. The reference crossed axis angle θ1 is a crossed axis angle determined based on the torsion angle φw of the gear of the workpiece W1 on the reference circle and the torsion angle φt of the threaded grindstone T on the reference circle. Specifically, in a state in which the tooth trace direction D_Tr of the portion to be ground on the workpiece W1 coincides with the blade trace direction on the reference circle of the convex blade ground by the threaded grindstone T, the rotational axis B1 of the workpiece W1 and The crossed-axis angle between the threaded grindstone T and the rotation axis C is the reference crossed-axis angle θ1.

If the tooth flank of the gear of the workpiece W1 is ground by the threaded grindstone T in a state where the reference axis crossing angle θ1 is set, as shown in FIGS. A grinding point P1a on one tooth flank and a grinding point P1b on the other tooth flank are ground by the threaded grindstone T. As shown in FIG. The grinding points P1a and P1b are positioned on the rotational axis C of the threaded grindstone T when projected in the direction shown in FIG. Also, when projected in the direction shown in FIG. 6(c), the grinding points P1a and P1b are positioned on Xt and Xw.

As shown in FIG. 6(c), the threaded grindstone T rotates around the C-axis at the grinding points P1a and P1b, so the abrasive grains of the convex edge of the threaded grindstone T rotate around the C-axis. Therefore, at the grinding points P1a and P1b, the abrasive grains of the convex blade of the threaded grindstone T move upward in FIG. 6(c).

At the grinding points P1a and P1b, respectively, the moving direction vectors of the abrasive grains of the convex blade of the threaded grindstone T are expressed as V1a and V1b. Then, as shown in FIG. 6(c), when viewed from the axial direction of the threaded grindstone T (when projected in the axial direction of the threaded grindstone T), the tooth trace direction D_Tr of the gear of the workpiece W1, The velocity vectors (components of V1a and V1b on the paper in FIG. 6(c)) due to the rotation of the threaded grindstone T at the grinding points P1a and P1b on the convex blade of the threaded grindstone T match. In other words, when projected onto the working plane representing the tooth surface of the workpiece W1, the component of the tooth trace direction D_Tr of the gear of the workpiece W1 on the working plane and the rotation of the threaded grindstone T at the grinding points P1a and P1b The component on the plane of action of the velocity vector by

FIG. 7(a), which is enlarged, shows the movement direction vector V1a of the abrasive grains of the convex blade of the threaded grindstone T at the grinding point P1a on one tooth surface of the workpiece W1. Then, as shown in FIGS. 7B and 7C, grinding streaks Gr_W1 are formed by the abrasive grains of the convex edge of the threaded grindstone T on one tooth surface of the workpiece W1. That is, the grinding streak Gr_W1 is formed substantially parallel to the tooth trace direction D_Tr of the tooth surface of the workpiece W1. However, in detail, the grinding streak Gr_W1 is not linear, but is composed of a large number of small-angle arcs, but as a whole, it is substantially parallel to the tooth trace direction D_Tr. Therefore, the reference crossed axis angle θ1 can be said to be the crossed axis angle for forming the grinding streak Gr_W1 formed on the tooth surface of the gear of the workpiece W1 by the threaded grindstone T in a direction parallel to the tooth trace direction D_Tr. .

Return to Figure 5 for explanation. After the reference crossed axis angle θ1 is determined (S3), the corrected crossed axis angle Δθ is determined (S4). As shown in FIG. 4A, the corrected crossed axis angle Δθ is such that the grinding streak Gr1 formed on the tooth flank of the gear of the workpiece W by the threaded grindstone T is set at a predetermined angle with respect to the tooth trace direction D_Tr. It is the crossed axis angle for forming Σ in the tilted direction.

The corrected axis crossing angle Δθ will be described with reference to FIGS. 8 and 9. FIG. As shown in FIGS. 8A and 8B, the corrected crossed axes angle Δθ is an additional crossed axes angle to the reference crossed axes angle θ1. In other words, by additionally providing the corrected crossed axes angle Δθ, the crossed axes angle between the rotation axis B2 of the workpiece W2 and the rotation axis C of the threaded grinding wheel T becomes equal to the reference crossed axes angle θ1 and the corrected crossed axes angle Δθ . Note that the corrected axis crossing angle Δθ may be a positive value or a negative value.

Then, when the tooth flank of the gear of the workpiece W1 is ground by the threaded grindstone T in a state where the composite crossed axes angle θ2 obtained by adding the corrected crossed axes angle Δθ to the reference crossed axes angle θ1 is set, FIG. As shown in (b) and (c), the grinding point P2a on one tooth surface and the grinding point P2b on the other tooth surface of the workpiece W2 are ground by the threaded grindstone T. As shown in FIG. When projected in the direction shown in FIG. 8B, the grinding point P2a is positioned above the rotation axis C of the threaded grindstone T, and the grinding point P2b is positioned below the rotation axis C of the threaded grindstone T. do. When projected in the direction shown in FIG. 8C, the grinding point P2a is located above Xt and Xw, and the grinding point P2b is located below Xt and Xw.

As shown in FIG. 8(c), the threaded grindstone T rotates around the C-axis at the grinding points P2a and P2b, so the abrasive grains on the convex edge of the threaded grindstone T rotate around the C-axis. Therefore, at the grinding point P2a, the abrasive grains of the convex edge of the threaded grindstone T move in the upper right direction in FIG. 8(c). On the other hand, at the grinding point P2b, the abrasive grains of the convex edge of the threaded grindstone T move leftward in FIG. 8(c).

At the grinding points P2a and P2b, respectively, the moving direction vectors of the abrasive grains of the convex blade of the threaded grindstone T are expressed as V2a and V2b. As shown in FIG. 8C, when viewed from the axial direction of the threaded grindstone T (when projected in the axial direction of the threaded grindstone T), the tooth trace direction D_Tr of the gear of the workpiece W2 and the threaded grindstone The velocity vectors (components of V2a and V2b on the paper surface of FIG. 8(c)) due to the rotation of the threaded grindstone T at the grinding points P2a and P2b on the convex edge of T have angles α and β. In other words, when projected onto the working plane representing the tooth surface of the workpiece W2, the component of the tooth trace direction D_Tr of the gear of the workpiece W2 on the working plane and the rotation of the threaded grindstone T at the grinding points P2a and P2b The component on the plane of action of the velocity vector by has an angle.

FIG. 9(a), which is enlarged, shows the movement direction vector V2a of the abrasive grains of the convex edge of the threaded grindstone T at the grinding point P2a on one tooth surface of the workpiece W2. Then, as shown in FIGS. 9B and 9C, grinding streaks Gr_W2 are formed by the abrasive grains of the convex edge of the threaded grindstone T on one tooth surface of the workpiece W2. That is, the grinding streaks Gr_W2 are formed in a direction inclined by a predetermined angle Σ with respect to the tooth trace direction D_Tr of the tooth surface of the workpiece W2. However, although the grinding streaks Gr_W2 are not straight lines but consist of arcs with a large number of small angles, as a whole they are formed in a direction inclined at a predetermined angle Σ with respect to the tooth trace direction D_Tr. be done. Therefore, the corrected crossed axis angle Δθ forms grinding streaks Gr_W2 formed on the tooth surface of the gear of the workpiece W1 by the threaded grindstone T in a direction inclined by a predetermined angle Σ with respect to the tooth trace direction D_Tr. It can be said that it is the crossed axis angle for

As shown in FIG. 9(c), the grinding streak Gr_W2 on one tooth surface of the gear of the workpiece W2 is formed in a direction inclined by a predetermined positive angle Σ with respect to the tooth trace direction D_Tr. Although not shown, the grinding streak Gr_W2 on the other tooth surface of the gear of the workpiece W2 is formed in a direction inclined at a predetermined negative angle (−Σ) with respect to the tooth trace direction D_Tr.

The method of determining the corrected crossed axes angle Δθ, that is, the details of the corrected crossed axes angle determination step S4 will be described with reference to FIGS. 5 and 10 to 12. FIG. First, as shown in FIG. 5, a provisional corrected crossed axis angle Δθ' is determined (S41). The temporarily corrected crossed-axis angle Δθ' that is determined first is an arbitrary value, and serves as an initial value for determining the corrected crossed-axis angle Δθ.

Subsequently, as shown in FIGS. 5 and 10, when the workpiece W2 is rotated around the B2 axis, the velocity vector Gm of the grinding point P2 on the tooth surface of the gear of the workpiece W2, the tooth surface A line component vector Gv (referred to as a tooth surface normal component vector) is calculated (S42). Here, the grinding points P2 are set as a plurality of discrete points on a cross section perpendicular to the tooth trace direction D_Tr on the tooth surface of the workpiece W2. The plurality of grinding points P2 are points indicated by white circles and black circles in FIG. Also, in FIG. 10, the velocity vector Gm and the normal component vector Gv are for the grinding point P2 indicated by the black circle.

Subsequently, a provisional corrected crossed axes angle Δθ' is given as the corrected crossed axes angle Δθ. In other words, a state is set in which the provisional composite crossed axes angle θ2′ is obtained by adding the provisional corrected crossed axes angle Δθ′ to the reference crossed axes angle θ1. Here, as shown in FIG. 11, when the threaded grindstone T is moved relative to the workpiece W2, the velocity vector (referred to as grindstone velocity vector) of the point Pt' on the convex edge of the threaded grindstone T is be Tm'. Then, between the tooth surface normal component vector Gv at the grinding point P2 on the tooth surface of the workpiece W2 shown in FIG. A component Tv′ in the direction of the line component vector Gv (referred to as a grindstone normal component vector) is calculated. In other words, the direction of the tooth surface normal component vector Gv in the workpiece W2 and the direction of the grindstone normal component vector Tv' in the threaded grindstone T match. Then, a point Pt' on the convex edge of the threaded grindstone T when the magnitude of the tooth surface normal vector Gv on the workpiece W2 and the grindstone normal vector Tv' on the threaded grindstone T match is determined as follows: demand. The obtained point Pt' on the protruding edge is set as the temporary grindstone point Pt' (S43).

Subsequently, as shown in FIGS. 5 and 11, the tangent vector Th' of the convex blade of the threaded grindstone T is calculated (S44). Specifically, the normal cross-sectional shape of the convex edge of the threaded grindstone T is determined by obtaining the temporary grindstone point Pt' in S43, as indicated by the chain double-dashed line in FIG. Then, out of the grinding wheel speed vector Tm' at the temporary grinding wheel point Pt' on the convex edge of the threaded grinding wheel T, the tangential vector Th', which is the vector in the direction orthogonal to the perpendicular cross section of the convex edge, is calculated. This tangential vector Th' corresponds to the moving direction vector V2a of the abrasive grains of the convex blade of the threaded grindstone T shown in FIG. 9(a).

Next, whether the tangential vector Th' of the threaded grindstone T at a predetermined grinding point P2 (for example, the central point of the tooth depth) on the tooth surface of the workpiece W2 matches the direction of the preset target grinding streak Gr_W2. It is determined whether or not (S45). At this time, when comparing with the advancing direction angle of engagement, the tangential vector Th' is projected onto the action plane representing the tooth surface of the workpiece W2, and compared with the angle on the action plane.

If it is determined that the tangential vector Th' matches the direction of the target grinding streak Gr_W2 (S45: Yes), the provisional wheel point Pt' is determined as the wheel shape point Pt, and the provisional correction crossed axis angle when they match. Δθ' is determined as the corrected crossed axis angle Δθ (S46). On the other hand, if it is determined that the tangential vector Th' does not match the direction of the target grinding streak Gr_W2 (S45: No), the process returns to S41 to determine a new provisional correction crossed axis angle Δθ', and the processing from S42 onwards is performed. conduct.

That is, in the correction crossed axis angle determination step S4, the tangent vector Th' of the threaded grindstone T at a predetermined grinding point P2 (for example, the central point of the tooth depth) on the tooth surface of the workpiece W2 is the target grinding streak Gr_W2. Find the temporary corrected crossed axis angle Δθ' that will match the direction. Then, in the process of the corrected crossed axis angle determination step S4, as shown in FIG. 10, the same process is performed for a plurality of grinding points P2 on the tooth surface of the workpiece W2, and the grindstone shape corresponding to all the grinding points P2 is determined. A point Pt is determined.

Subsequently, as shown in FIG. 5, a combined crossed axes angle θ2 is determined by combining the reference crossed axes angle θ1 determined in S3 and the corrected crossed axes angle Δθ determined in S4 (S5).

Subsequently, as shown in FIG. 5, in a state where the crossed-axis angle between the rotation axis B2 of the workpiece W2 and the rotation axis C of the threaded grindstone T is set to a combined crossed-axis angle θ2, based on a plurality of grindstone shape points Pt, to determine the shape of the convex edge of the threaded grindstone T (S6). Specifically, as shown in FIG. 12, the cross-sectional shape of the convex blade of the threaded grindstone T is determined based on the grindstone shape points Pt corresponding to the respective grinding points P2 on the tooth surface of the gear of the workpiece W2.

By the way, if the corrected crossed axes angle Δθ is zero, that is, the crossed axes angle between the rotation axis B1 of the workpiece W1 and the rotation axis C of the threaded grindstone T as shown in FIGS. When the angle is θ1, the cross-sectional shape of the convex edge of the threaded grindstone T becomes the shape shown in FIG. That is, the grindstone shape point Pt corresponding to each grinding point P1 on the tooth surface of the gear of the workpiece W1 is determined, and the cross-sectional shape of the convex blade of the threaded grindstone T is determined based on the grindstone shape point Pt.

The cross-sectional shape of the convex blade of the threaded grindstone T when the corrected crossed axis angle Δθ shown in FIG. 12 and 13) is smaller and the amount of protrusion (vertical height in FIGS. 12 and 13) is larger.

As described above, the grinding condition determining section 8 determines the reference crossed axis angle θ1 and the corrected crossed axis angle Δθ, and combines the determined reference crossed axis angle θ1 and the corrected crossed axis angle Δθ to obtain the synthetic axis. The intersection angle θ2 is determined as one of the grinding conditions. Further, the grinding condition determination unit 8 determines the convex blade shape of the threaded grindstone T as one of the grinding conditions. Then, the determined convex blade of the threaded grindstone T is configured so as to be able to grind both tooth flanks of the gear on the workpiece W2 at the same time.

5. Processing by Grinding Processing Unit 9 Processing by the grinding processing unit 9 (grinding process Sb) will be described. The grinding processing unit 9 applies the grinding conditions determined by the grinding condition determination unit 8 and grinds the tooth flank of the gear of the workpiece W with the threaded grindstone T. As shown in FIG.

The grinding processing unit 9 positions the workpiece W2, which is a helical gear, and the threaded grindstone T, as shown in FIGS. The crossed-axis angle between the rotation axis B2 of the workpiece W2 and the rotation axis C of the threaded grindstone T is set to the combined crossed-axis angle θ2. Then, the workpiece W2 and the threaded grindstone T are rotated synchronously, and the threaded grindstone T is relatively moved in a direction parallel to the rotation axis B2 of the workpiece W2.

Then, as shown in FIG. 8(b), the threaded grindstone T simultaneously grinds both tooth flanks of the gear on the workpiece W2. As shown in FIGS. 9B and 9C, grinding streaks Gr_W2 are formed by the threaded grindstone T on the tooth surface of the ground workpiece W2. Grinding streaks Gr_W2 to be formed are formed in a direction inclined by a predetermined angle Σ with respect to the tooth trace direction D_Tr. In particular, the extending direction of the grinding streak Gr_W2 that is formed coincides with the mesh advancing direction D_La on the tooth surface of the workpiece W2. That is, the predetermined angle Σ is set to the angle formed by the tooth trace direction D_Tr of the tooth surface of the driven gear Gb (shown in FIG. 3) serving as the workpiece W2 and the mesh advancing direction D_La of the drive gear Ga serving as the mating gear. ing. As a result, meshing noise can be reduced.

6. Effect According to this embodiment, when grinding the tooth surface of the gear of the workpiece W2 using the threaded grindstone T, the crossed axis angle between the rotation axis B2 of the workpiece W2 and the rotation axis C of the threaded grindstone T is set. The crossed axes angle obtained by the torsion angle φw of the gear of the workpiece W2 on the reference circle and the torsion angle φt on the reference circle of the threaded grindstone T is defined as the reference crossed axes angle θ1. In this embodiment, the gear of workpiece W2 is a helical gear. Therefore, the helix angle φw on the reference circle of the gear of the workpiece W2 is not 0°. In this case, the reference axis crossing angle θ1 is an angle that takes into account the torsion angle φw of the gear of the workpiece W2 with respect to the torsion angle φt of the threaded grindstone T on the reference circle.

Assuming that the crossed axes angle is set to the reference crossed axes angle θ1 as shown in FIGS. Grinding streaks Gr_W1 formed on the tooth surface are parallel to the tooth trace direction D_Tr of the tooth surface. Therefore, in this embodiment, as shown in FIGS. 8 and 9, the crossed axes angle between the rotation axis B2 of the workpiece W2 and the rotation axis C of the threaded grindstone T is defined as a reference crossed axes angle .theta.1 and a corrected crossed axes angle .DELTA..theta. is defined as a combined crossed axis angle θ2.

The corrected crossed axis angle Δθ is for forming the grinding streaks Gr_W2 formed on the tooth surface of the gear of the workpiece W2 by the threaded grindstone T in a direction inclined at a predetermined angle Σ with respect to the tooth trace direction D_Tr. is the crossed axis angle. That is, by setting the crossed axes angle during grinding to a synthetic crossed axes angle θ2 obtained by synthesizing the reference crossed axes angle θ1 and the corrected crossed axes angle Δθ, the grinding streaks Gr_W2 are aligned in a direction parallel to the tooth trace direction D_Tr. Instead, the direction is inclined toward the tooth trace direction D_Tr.

Since the grinding streaks Gr_W2 can be formed in a direction inclined in the tooth trace direction D_Tr, for example, in the meshing between the gear to be ground and the mating gear, the grinding is performed in the direction D_La of engagement on the tooth surface of the gear to be ground. The direction in which the streak Gr_W2 extends can be matched. When the two directions match, the mating gear Ga does not move over the grinding streak Gr_W2 on the tooth surface during the progress of gear meshing. Since the grinding streak Gr_W2 is not driven over, it is possible to reduce the noise generated in the meshing of the gears.

Further, even if the direction in which the grinding streak Gr_W2 extends does not coincide with the meshing advancing direction D_La, by bringing the extending direction of the grinding streak Gr_W2 closer to the meshing advancing direction D_La, it is possible to overcome the grinding streak Gr_W2. can be reduced. As a result, it is possible to reduce the noise generated in the meshing of the gears.

In particular, by using a helical gear as the workpiece W2, it is possible to make the direction in which the grinding streaks Gr_W2 extend substantially coincide with the mesh advancing direction D_La. Therefore, it is possible to reduce the noise generated in the meshing of the helical gears.

As described above, it is possible to reduce noise due to the influence of the steps on the tooth surfaces of the gears in the meshing of the gears without additional machining.

In this embodiment, as shown in FIG. 8, the threaded grindstone T is configured to be able to grind both tooth flanks of the gear on the workpiece W2 at the same time. Both tooth flanks of the gear on the workpiece W2 are ground simultaneously by the shaped grindstone T. Then, as shown in FIG. 9, the grinding streaks Gr_W2 on one tooth surface of the gear of the workpiece W2 are formed in a direction inclined at a predetermined positive angle Σ with respect to the tooth trace direction D_Tr. On the other hand, the grinding streaks Gr_W2 on the other tooth surface of the gear of the workpiece W2 are formed in a direction inclined at a predetermined negative angle (−Σ) with respect to the tooth trace direction D_Tr. In this way, when the direction of the grinding streak Gr_W2 satisfies the above conditions, both tooth flanks can be ground at the same time, and the number of grinding steps can be reduced.

(Embodiment 2)
In Embodiment 1, the workpiece W is described as a helical gear having a helix angle φw. Alternatively, the workpiece W can be a spur gear as shown in FIG. When the workpiece W is a spur gear, the torsion angle on the reference circle is 0°. Then, as shown in FIG. 14, in the workpiece W, which is a spur gear, the meshing advancing direction D_La of the mating gear coincides with the tooth depth direction D_Hi.

If the extending direction of the grinding streaks Gr_W were formed parallel to the tooth trace direction D_Tr, the meshing points would cross over the grinding streaks Gr_W a large number of times, causing meshing noise. Therefore, as shown in FIG. 14, the extending direction of the grinding streaks Gr_W is set at an angle inclined with respect to the tooth trace direction D_Tr and at an angle inclined with respect to the tooth depth direction D_Hi. That is, the extending direction of the grinding streaks Gr_W is inclined with respect to the mesh advancing direction D_La, but has a smaller angle than orthogonal.

Here, as described in the first embodiment, by making the extending direction of the grinding streaks Gr_W coincide with the mesh advancing direction D_La, the noise caused by the meshing points overcoming the grinding streaks Gr_W can be greatly reduced. can be reduced. However, the grinding streak Gr_W cannot be formed in a direction parallel to the tooth depth direction D_Hi. Therefore, the grinding streak Gr_W is set in a direction as close as possible to the mesh advancing direction D_La.

(Embodiment 3)
In the above embodiment, the case where both tooth flanks of the gear on the workpiece W are simultaneously ground by the threaded grindstone T is taken as an example. Alternatively, the threaded grindstone T may be configured to grind only one tooth flank of the gear on the workpiece W. The threaded grindstone T is formed as shown in FIG. That is, the convex blade of the threaded grindstone T has only one side of the convex blade of the threaded grindstone T determined in the first embodiment.

In Embodiment 1, when the extending direction of the grinding streak Gr_W2 on one tooth flank is determined by grinding both tooth flanks of the workpiece W at the same time, the grinding streak Gr_W2 on the other tooth flank is inevitably ground. The extending direction of Gr_W2 is determined. Therefore, in order to freely set the extending direction of the grinding streak Gr_W2 on each tooth surface, it is preferable to use a threaded grindstone T as shown in FIG. In this case, one tooth flank is ground by a threaded grindstone T shown in FIG. 15, and the other tooth flank is ground by a threaded grindstone (not shown).

Claims

A gear grinding method for grinding the tooth surface of a gear (Gb1) using a threaded grindstone (T),
The crossed axes angle between the rotation axis (B2) of the workpiece (W2) and the rotation axis (C) of the threaded grindstone is a synthetic crossed axes obtained by synthesizing the reference crossed axes angle (θ1) and the corrected crossed axes angle (Δθ). A grinding step of grinding the tooth flank of the gear by setting the angle (θ2), rotating the threaded grindstone and the workpiece synchronously, and relatively moving the threaded grindstone in a direction parallel to the rotation axis of the workpiece. (Sb);
The reference crossed axis angle is a crossed axis angle determined based on the torsion angle on the reference circle (φw) of the gear and the torsion angle on the reference circle (φt) of the threaded grindstone,
The corrected crossed-axis angle forms grinding streaks (Gr_W2) formed on the tooth surface of the gear by the threaded grindstone in a direction that is inclined at a predetermined angle (Σ) with respect to the tooth trace direction (D_Tr). gear grinding method, which is the crossed axes angle for
2. The reference crossed axis angle according to claim 1, wherein the crossed axis angle is an angle for forming the grinding streaks formed on the tooth surface of the gear by the threaded grindstone in a direction parallel to the tooth trace direction. gear grinding method.
2. A speed vector due to the rotation of the threaded grindstone at a grinding point on the convex edge of the threaded grindstone and a tooth trace direction of the gear form an angle when viewed from the axial direction of the threaded grindstone. 3. The gear grinding method according to 1 or 2.
The threaded grindstone is configured to be able to grind both tooth flanks of the gear in the workpiece at the same time,
The grinding streaks on one tooth surface of the gear are formed in a direction inclined at a predetermined positive angle with respect to the tooth trace direction,
The grinding streaks on the other tooth surface of the gear are formed in a direction inclined at a predetermined negative angle with respect to the tooth trace direction,
The gear grinding method according to any one of claims 1 to 3, wherein in the grinding step, both tooth flanks of the gear on the workpiece are ground simultaneously with the threaded grindstone.
The threaded grindstone is configured to be able to grind only one tooth surface of the gear in the workpiece,
The gear grinding method according to any one of claims 1 to 3, wherein in the grinding step, the threaded grindstone grinds only one tooth surface of the gear on the workpiece.
a grinding condition determination step (Sa) for determining grinding conditions including the convex edge shape of the threaded grindstone and the combined crossed axis angle;
the grinding step (Sb) of grinding the tooth surface of the gear using the threaded grindstone based on the determined grinding conditions;
Gear grinding method according to any one of claims 1 to 5, comprising
The grinding condition determination step (Sa) includes:
a reference crossed axis angle determination step (S3) of determining the reference crossed axis angle based on the torsion angle on the reference circle of the gear and the torsion angle on the reference circle of the threaded grindstone;
Determining the corrected crossed axis angle for forming the grinding streaks formed on the tooth surface of the gear in the workpiece by the threaded grindstone in a direction inclined at the predetermined angle with respect to the tooth trace direction. A correction crossed axis angle determination step (S4) for
A convex blade shape determining step (S6) of determining the convex blade shape of the threaded grindstone in a state where the crossed axes angle between the rotation axis of the workpiece and the rotation axis of the threaded grindstone is the composite crossed axes angle. and,
The gear grinding method according to claim 6, comprising:
The corrected crossed axis angle determination step includes:
calculating a tooth surface normal component vector (Gv), which is a normal component vector of the tooth surface of the speed vector of the grinding point on the tooth surface of the gear when the workpiece is rotated;
When the provisional corrected crossed axes angle is set as the corrected crossed axes angle and the threaded grindstone is moved relative to the workpiece, the provisional grindstone point (Pt '), the grindstone normal component vector (Tv′), which is a component in the direction of the tooth surface normal component vector, is calculated, and the magnitude of the tooth surface normal component vector and the grindstone normal component vector Determine the temporary grinding wheel point when the size matches,
calculating a tangent vector (Th') of the convex blade out of the velocity vectors of the determined temporary grinding wheel point;
It is determined whether or not the tangential vector coincides with the direction of the grinding streak set in advance, and the temporary grindstone point when the tangential vector coincides is determined as the grindstone shape point (Pt), determining a corrected crossed axis angle as the corrected crossed axis angle;
8. The gear grinding method according to claim 7, wherein the convex edge shape of the threaded grindstone is determined based on the determined grindstone shape point.
the gear is a helical gear,
The gear grinding method according to any one of claims 1 to 8, wherein the predetermined angle is set to an angle formed by a tooth trace direction of the tooth surface of the gear and a direction in which the mating gear meshes with the mating gear.
the gear is a spur gear;
The predetermined angle is an angle inclined with respect to the tooth trace direction of the tooth flank of the gear, and is set at an angle inclined with respect to the direction in which meshing with the mating gear progresses. Gear grinding method according to.
A gear grinding device (1) for grinding the tooth surface of a gear (Gb1) using a threaded grindstone (T),
The crossed axes angle between the rotation axis (B2) of the workpiece (W2) and the rotation axis (C) of the threaded grindstone is a synthetic crossed axes obtained by synthesizing the reference crossed axes angle (θ1) and the corrected crossed axes angle (Δθ). A grinding process in which the angle (θ2) is set, the threaded grindstone and the workpiece are rotated synchronously, and the tooth surface of the gear is ground by relatively moving the threaded grindstone in a direction parallel to the rotation axis of the workpiece. comprising part (9),
The reference crossed axis angle is a crossed axis angle determined based on the torsion angle on the reference circle (φw) of the gear and the torsion angle on the reference circle (φt) of the threaded grindstone,
The corrected crossed-axis angle forms grinding streaks (Gr_W2) formed on the tooth surface of the gear by the threaded grindstone in a direction that is inclined at a predetermined angle (Σ) with respect to the tooth trace direction (D_Tr). gear grinding machine, which is the crossed axes angle for
a grinding condition determination unit (8) that determines grinding conditions including the convex edge shape of the threaded grindstone and the combined crossed axis angle;
the grinding processing section (9) for grinding the tooth surface of the gear using the threaded grindstone based on the determined grinding conditions;
12. The gear grinding apparatus of claim 11, comprising: